Various fixes due to outdated code, Windows, and bad commands

client/Dockerfile

@@ -1,4 +1,4 @@
-FROM centos
+FROM centos:7
 
 ADD client.bash client.bash
 
@@ -8,4 +8,4 @@ ARG port=8000
 ENV server $server
 ENV port $port
 
-CMD ./client.bash $server $port
+CMD /bin/bash ./client.bash $server $port

docker-compose.yml

@@ -1,18 +1,18 @@
-version: '3'
-
-services:
-
-  server:
-    build:
-      context: ./server
-    ports:
-      - "8000:8000"
-
-  client:
-    build:
-      context: ./client
-      args:
-        server: 'server'
-        port: 8000
-    links:
-      - "server"
+version: '3'
+
+services:
+
+  server:
+    build:
+      context: ./server
+    ports:
+      - "8000:8000"
+
+  client:
+    build:
+      context: ./client
+      args:
+        server: 'server'
+        port: 8000
+    links:
+      - "server"